Morphological fractions and in vitro fermentation characteristics of five endosperm types maize stover harvested at two maturity stages

摘要

This study was conducted to estimate the effect of maize endosperm type, e.g., waxy, conventional, fodder, sweet, and high oil, and maturity stage on chemical composition and in vitro fermentation characteristics of morphological fractions. Whole maize stover was separated into four fractions, including leaf blade, leaf sheath, stem and husk. The proportion of leaf blade, leaf sheath and husk, and crude protein (CP) and phosphorus (P) contents decreased, whereas the proportion of stem and fibre content increased with the increasing of maturity stage. High oil, sweet, fodder and conventional had the highest proportion in leaf blade, leaf sheath, stem and husk, respectively. Leaf blade had the highest CP and P contents and husk had the highest neutral detergent fibre content. Conventional had the highest (P<0.05) acid detergent fibre content but the lowest (P<0.05) CP content than the others. Fodder and high oil had the highest P and organic matter (OM) content. In vitro gas production parameters of b, a+b, in vitro OM disappearance (IVOMD), and concentration of total volatile fatty acid (TVFA) decreased (P<0.05) with the increase of maturity. Maize stover parts from waxy variety had the highest values of b, c and a+b, whereas the morphological fractions from conventional variety had the highest IVOMD. The morphological fractions differed in c value and potential gas production in the following order: husk > leaf sheath > stem > leaf blade. The highest and lowest values of IVOMD were observed in husk and stem, respectively. The highest TVFA concentration, molar proportion of acetate and propionate were noted in high oil, waxy and sweet, respectively. The result indicated that the nutritive value of maize stover could be improved through the selection of endosperm type and appropriate maturity stage.